I can't help remembering a comic book I read over ten years ago (Common Grounds), which I think fits the mentality of the fat acceptance movement. In issue four the superhero, Knockout, enters a weight loss support group for obese superheroes, she finds out that any progress is thwarted by the support group's leader, Red Fox. He despises the idea of the group losing weight since it would be doing what the "thin fascists" want and those that do are "self-hating". (He demands that people use the term "dense" instead of fat.) Runs the support group at a diner that specializes in donuts to stick it to others and their perceptions on fat people. He wants to start protests towards fat acceptance, encourage the teaching of fat historical figures and celebrities in schools, etc. instead of giving the group what they need. Just like a FA, he ignores the physical problems that being really fat can bring (he can't even run around and fight crime like he used to) and how it effects being a superhero. In the end, Knockout tells him off and exits with the rest of the group, leaving Red Fox alone and realizing he has a problem.
If this story came out today, it would be very relevant since it perfectly captures the FA's behavior. And get tons of hate (no pun intended) from those people.